Navy spokesman says Michael Dean’s comments to CNN — that sounds detected in Indian Ocean in April were unrelated to missing jet — were “speculative and premature”

CANBERRA, AUSTRALIA—A U.S. Navy spokesman has dismissed as “speculative and premature” an American expert’s reported comments that the acoustic “pings” at the centre of the search for the missing Malaysian plane did not come from the jet’s back boxes.

CNN reported the navy’s civilian deputy director of ocean engineering, Michael Dean, had said most countries now agreed that the sounds detected by the Navy’s Towed Ping Locator in April in the southern Indian Ocean came from a man-made source unrelated to the jet, which vanished March 8 with 239 people on board.

“Mike Dean’s comments today were speculative and premature, as we continue to work with our partners to more thoroughly understand the data acquired by the Towed Pinger Locator,” U.S. Navy spokesman Chris Johnson said in a statement, referring to Australia and Malaysia.

The navy would defer to Australia, as the lead in the Indian Ocean search effort, to make additional information known at the appropriate time, Johnson said.

Australia’s Joint Agency Co-ordination Centre did not immediately respond to requests for comment to the report on Thursday. Dean, who is based in Washington, could not be immediately reached for comment.

Not a single piece of the Boeing 777 has been found after it disappeared during a flight from Kuala Lumpur to Beijing. Satellite analysis led authorities to believe that Malaysia Airlines Flight 370 had diverted sharply from its flight path and flew south to the Indian Ocean.

Officials had described the detection of four series of “pings” in the area where the satellite data indicated was the likely crash site as their best lead in the search.

The signals appeared to be consistent with those from aircraft black boxes, which contain flight data and cockpit voice recordings. The locator beacons have a battery life of about a month, so it is presumed they have died.

An intensive search of the seabed in that area by an unmanned submersible has not turned up any sign of the plane.

Earlier this week, the Malaysian government released reams of raw satellite data it used to determine that the flight ended in the southern Indian Ocean, a step long demanded by the families of some of the passengers on board.

The conclusion is based on complex calculations derived largely from brief hourly transmissions or “handshakes” between the plane and a communications satellite operated by Britain’s Inmarsat company.

But while the 45 pages of information may help satisfy a desire for more transparency in a much criticized investigation, experts say it’s unlikely to solve the mystery of Flight 370. Theories range from mechanical failure to hijacking or pilot murder-suicide.